Help with updating from PHP 5 to PHP 7

Hello,

I am not sure if it is o.k. to ask for help on this mailing list. 
Unfortunately at stackoverflow.com nobody who is familiar with 
php-extensions seems to be around.
I found this guide for upgrading PHP: 
https://wiki.php.net/phpng-upgrading. And I searched other packages to 
see how they did it. I managed that the package I try to update compiles 
without errors, but I get some warnings and one of those at least is 
still breaking the functionality of the package.

Here is the diff of one function I changed that now breaks. Can somebody 
tell me where I am wrong?

PHP_FUNCTION(scard_connect)
{
   DWORD dwPreferredProtocol = SCARD_PROTOCOL_T1|SCARD_PROTOCOL_T0;
   DWORD dwCurrentProtocol;
   SCARDHANDLE hCard = 0;
   LONG rc = 0;
   zval* ctx_res;
- zval* current_protocol;
+ zval current_protocol;
   SCARDCONTEXT context;
   char *strReaderName;
   int strReaderNameLen;

- MAKE_STD_ZVAL(current_protocol);
- ZVAL_LONG(current_protocol,0);
+ ZVAL_LONG(&current_protocol,0);

   if (zend_parse_parameters(ZEND_NUM_ARGS() TSRMLS_CC, "rs|lz", 
&ctx_res, &strReaderName, &strReaderNameLen, 
&dwPreferredProtocol,&current_protocol) == FAILURE) {
    RETURN_NULL();
   }

- 
ZEND_FETCH_RESOURCE(context,SCARDCONTEXT,&ctx_res,-1,PHP_PCSC_CTX_RES_NAME,le_pcsc_ctx_res);

+  if ((context = (SCARDCONTEXT)zend_fetch_resource(Z_RES_P(ctx_res), 
PHP_PCSC_CTX_RES_NAME, le_pcsc_ctx_res)) == NULL) {
+        RETURN_FALSE;
+  }

   rc = SCardConnect(context, strReaderName, SCARD_SHARE_SHARED, 
dwPreferredProtocol, &hCard, &dwCurrentProtocol);
   if (rc != SCARD_S_SUCCESS) {
     PCSC_G(last_errno)=rc;
     RETURN_FALSE;
   }
-  ZVAL_LONG(current_protocol,dwCurrentProtocol);
+ ZVAL_LONG(&current_protocol,dwCurrentProtocol);

- ZEND_REGISTER_RESOURCE(return_value,(void*)hCard,le_pcsc_conn_res);
+ RETURN_RES(zend_register_resource((void*)hCard,le_pcsc_conn_res));

}


Thanks in advance,
Benedikt.